Bit holder



,May 2, 19330 J N BAKER 1,907,399

BIT HOLDER Filed Oct. 7, 1950 Patented May 2, 1933 S EAES ra OFFICE JAMES N; BAKER, OE TO'W'SON, IaEAEYTL-AEED, ASSIGHOE TO TI-IE BLACK AND DECKER MANUFACTURING COMPANY, OF TOW/SON, MARYLAND, A CORPORATION OF MARY- LAN D BIT HOLDER Application filed October 7, 1930. Serial No. 488,914.

In the operation of the various portable power hammers, pneumatic, electric and the like, a considerable element of danger is involved through the tendency to project the bit or steel from the tool when for any reason the motor is permitted to run with the bit out of contact with the work. While various means have been devised for retaining the bit in its socket, these, on account of their rigid character, are apt to be broken or are found so inconvenient to operate when the bit is changed, that they are discarded by the workman so that from a practical point of view they are wholly ineifective for the purpose in hand.

The present invention provides a bit holde of a resilient nature so that it avoids the danger of breaking due to the impact of the bit when it is projected forwardly by the action of the hammer when not in contact with the work. The bit holder or retaining device is also capable of instantaneous operation in releasing the bit to be removed and engaging the one newly inserted, the resilient feature contributing to the instantaneous operation of the retaining device and also serving to hold it in close engagement with the shank of the bit when in operation. The new bit holder is regardecl as of increased efliciency and its construction is at the same time greatly simplified and cheapencd as compared to those now in use.

In the accompanying drawing l have illustrated the tool retaining device or bit holder of the invention in the preferred form, the same being shown in its operative relation to the bit or steel as it is being called in practice and to the percussive tool or hammer, so much of the bit and percussive tool as is necessary to a full comprehension of the invention being shown in connection with the bit holder.

In the drawing:

Figure l is a bottom plan view of the nose of a portable power driven hammer or percussive tool equipped with a steel or bit, the latter being held in position by the retaining device of the invention.

Figure 2 is a vertical section on the line 2-2 of Figure 3 showing the nose of the percussive tool fragmentarily, the steel or bit and the retaining device also being shown in elevation, a portion at one end of the retaining device being broken away and shown in section and the other end in full.

Figure 3 is an elevation showing the same subject matter looking in a direction at right angles to the direction of observation in Figure 2. f

Referring to the drawing by numerals, each of which is used to indicate the same or similar parts in the different figures, the construction shown comprises the nose 1 of a percussive tool or hammer, having a socket 2 in which is seated the bit or steel 3, the same being held in position by the retaining device a, i 'hich is the subject of the invention.

In accordance with the prevailing practice, the bit or steel 3 is provided with a circumferential shoulder 5, which limits the extent to which the bit 3 can be inserted in the socket For the purpose'of positioning the bit the surface of the shoulder 5 at 6 disposed toward the socket end of the shank, contacts the outer end of the nose ofthe percussive tool at 7, theopposite surface of the shoulder 5 at 8 being disposed toward the operative end of the bit or steel which engages the work. The retaining device 4 comprises a yoke 9 which as seen in side elevation, Figure 2, is U shaped, and the cross arm of the ll at 10 is as shown in plan, Figure l, bent in the form of a horizontally disposed U or loop 11, which is preferably semicircular or substantially so and of a radius but slightly greater than that of the bit or steel shank which is ordinarily round so that it engages the same closely for about one'half of its periphery. However, the exact contour of the bit is not absolutely essential, the retaining device being capable of engaging an octagonal, a hexagonal or even a square bit or steel.

Referring now to Figure 3 and also to the bottom plan, Figure 1, it will be noted that the legs 14 of the loop 11 extend in a horizontal direction from the loop 11 well beyond the center of the shank of the bit or steel, and the legs 15 of the yoke 9 are inclined upwarde ly and backwardly fromthe ends of legs 14 in to the central axial plane which may be identified as the plane of the section, Figure 2, where it intersects the nose 1. The upper ends of these legs are flat as shown at 16, Figure 3, the plane of said end surfaces 16 being at right angles to the axis of the steel or bit 3, and the construction described being widely variable.

To cooperate with the retaining deviceof the invention, the nose 1 of the percussive tool or hammer is provided with two oppositely projecting lugs 17, 18, the central radial planes of which including the axis of the bit or steel or coincident with the plane of Figure 2 where it intersects nose 1. These lugs are bored at 20, 21, respectively, in a direction parallel to the axis of the bit and through these lugs as thus bored are passed two L shaped bolts 22, 2%, the feet of the respective Us at the lower ends of said bolts at 25 being passed through suitable holes 26 in the upper ends of the legs 15 of the yoke 9. The L shaped bolts 22, are provided at their ends opposite to the feed 24 with nuts 27 and suitable helical springs 28 encircle the shanks of these bolts, being compressed each between the adjacent lug 17, 18 on the hammer nose and the corresponding nut 27 so that the bolts 22, 24 are given an upward tendency pressing the flat surfaces ldori; upper ends of legs 15 against the bottom s u faces of ears or lugs 17, 18;. I

In theoperation ofiithe-deviceithei Q91) 11 in the cross,armz iQbfx-the artially 1;- circles and, prefera ly engage the sh ank: of .t11e steel! jor. 5b" b. 101i t' i QL hOUldQ n 1111 iihhfiniitllgibillrilfibyi projected for; mares-Bathe opera hammcrmechziniisiiiowhnithe-bit is not; int sl lwit li h onlott avorkyithetoiavardwsul'face 8" 1 shou d r 6w contests he; cross; arm? 1.0 git-the: y e ,9, at

vthe; rloo ml'li so {that its release froni the" ham;- anerenoseis presented; hen; itis desired \toereinoueo-th'e steel or bit,:the-yokelis swung biikwaljdly ligfiih st t1ie:.resistanfce at springs 28; the .fla'a surfaces 1 .333516, i29 substantiallyxat rightaangles "eetin fni corner. 2.3;.actin'g; in 'fihQihalbU-FB of? a cam onehenehdd in cont-act with? the surface i 'XZE"i the: corresponding lugs amid-$8143 -l h! ispr1a1gsr28.) 1 1lll i hl sbpfillfltlOIl 1 flata'smifacesl 16a @nthe ends ofthe legs oft-he lyioke fiiagleinstthelugsrlfh182i: HI have thtisl do scribed; specifically} i ancL-in deiai'l ;;a-'hih1rtainen mliodjbll l gath features inf agryt imm'ntionlinnth'e pireierredxfmm in 1 order that the manner of constructing, applying and using the invention may be fully understood, however, the specific terms herein are used descriptively rather than in a limiting sense, the scope of the invention being defined in the claim.

What I claim as new and desire to secure by Letters Patent is:

The combination in a portable powerdriven hammer having a nose portion with laterally extending lugs and a bit with a transverse shoulder, the lugs having surfaces disposed toward the work of a retainer comprising a yoke, the yoke having in cross-arm with a loop adapted to encircle the shank oi the bit beyond the shoulder, pins extending through the lugs and slidable therein parallel to the bit, the pins having pivots rigidly connected thereto and disposed at right angles to the pins, springs applying tension to the pins oppositely to the working stroke of the hammer, the yoke having cam membfiili formed on its respective ends and apentuned to receive the pivots on whichythe; aumneihr bers and the yoke ,rotazte'itheccanm iembei's having antially fiatisurfacesi'tna smiisr to the length oftheyoke;atlapteditooengage he i s it. ic syof thelugs whereby ;th-iyekeds helchby the; springs cooperating with theioanis 1n engagen1ent with the toolhhaiikasitidqoke bang; adap ed to; melt on said pivots, neifiovstantiall-yi flat surfaces; ad l 111( eiigagei the lugstohold th'e yokedn disengaged posetion t-he tension;of;the;springsiboiiigaitherehy increasediasi the yokeciisnroclge'rl into andiout of; Tonga geeiniitzwith itheashanksa nd slightly JTQJJQIXQdHVhGIT the yoke reaches? either entrenie position when Zone; or i the. otheri i'p iofiicagn surfaces:bearson the;lugs?- 31 :1. of fiifii'l'ifj l Signed by iner: atki'lowsdn, fBalt-imoi'e County, 'Marylaa' 

